What Is Roof Pitch?
Roof pitch describes how steep your roof is, expressed as a ratio of rise (vertical height) to run (horizontal distance). A "4/12 pitch" means the roof rises 4 inches for every 12 inches of horizontal run.
Pitch matters because it affects everything about your roofing project: which materials can be used, how much material is needed (steeper = more surface area), labor costs (steeper = harder to work on), and how well water and debris shed off the surface.
How to Measure Your Roof Pitch
Method 1: From the Attic (Safest)
- Go into your attic with a level, tape measure, and pencil
- Place the level horizontally against a rafter
- Mark 12 inches from the rafter along the level
- Measure the vertical distance from your 12-inch mark straight down to the rafter
- That measurement is your "rise" — the first number in your pitch ratio
Method 2: From Outside (More Accurate but Requires Ladder)
- Place a level against the roof edge, extending horizontally
- Mark 12 inches on the level from the roof surface
- Measure from the 12-inch mark down to the roof surface
- That vertical measurement is your rise per 12 inches of run
Common Roof Pitches in Pinellas County
| Pitch | Angle | Common On | Material Options |
|---|---|---|---|
| Flat-2/12 | 0-9.5° | Commercial, carports, patios | TPO, EPDM, modified bitumen |
| 3/12 | 14° | Ranch homes, Florida rooms | Low-slope shingles, metal, TPO |
| 4/12 | 18.4° | Most common FL residential | All materials |
| 5/12-6/12 | 22.6-26.6° | Standard residential | All materials |
| 7/12-9/12 | 30.3-36.9° | Older homes, colonial style | All materials, +labor cost |
| 10/12+ | 39.8°+ | Victorian, A-frame, dormers | All materials, +significant labor cost |
The most common residential roof pitch in Pinellas County is 4/12 to 5/12. Many Florida homes, especially those built in the 1960s-1990s, were designed with moderate pitches that balance water shedding with hurricane wind resistance. Very steep roofs (8/12+) create more wind uplift surface area, which isn't ideal in our hurricane zone.
How Pitch Affects Your Roofing Cost
Steeper roofs cost more for two reasons:
- More material: A 4/12 pitch adds about 5% to your flat footprint area. A 12/12 (45°) pitch adds 41%. That's 41% more shingles, underlayment, and flashing.
- Higher labor costs: Steeper roofs require safety harnesses, roof jacks (temporary footholds), and slower, more careful work. Expect 15-30% labor surcharges above 8/12 pitch.
Use our roof cost calculator to see how pitch affects your total roof replacement cost. Or take the "Do I Need a New Roof?" assessment to evaluate your current roof's condition.
Roof Pitch and Florida Building Code
Florida Building Code has specific requirements based on roof pitch:
- Roofs below 2/12 pitch require special low-slope roofing systems (no standard shingles)
- Most asphalt shingles require a minimum 4/12 pitch (some specialty products allow 2/12)
- Self-adhering underlayment requirements apply at all pitches in our wind zone
- Tile roofing has minimum pitch requirements varying by profile (barrel tile typically needs 3/12+)
- Metal roofing can be installed at pitches as low as 1/2:12 with proper seam detailing